Growing and Shrinking Marshmallows

Make marshmallows shrink and grow in vacuum chamber! You should be able to do this with a kitchen vacuum pack gadget such as a Seal-a-Meal.

What you need:

• Vacuum seal container, such as a Seal-a-Meal
• Marshmallows or Peeps candy

What to do:

1. Place the marshmallows or Peeps in the sealed container.
2. Attach the vacuum.
3. Start the vacuum and watch your marshmallows expand.
4. Turn off the vacuum. Do the marshmallows collapse?

What's happening:
Marshmallows contain tiny air bubbles. The air inside the marshmallows pushes out, while the air around the marshmallows pushes in. When air is pumped out of the container, reducing the air pressure, the air bubbles inside the marshmallow push outwards and cause the marshmallow to grow.

As the marshmallow grows, the air bubbles inside start to rupture. When you turn off the vacuum and allow air back in, the marshmallow shrinks back to normal size. But since some of the air bubbles have been destroyed, it wrinkles and collapses even further.